1. Field of the Invention
The present invention relates to improved apparatus and method for feeding and driving dowels into preformed cavities in a workpiece. In particular, the invention relates to a novel power operated dowel gun and system for rapidly feeding dowels to the gun, wherein the gun and system have a relatively simple and inexpensive design which results in exceptional reliability and durability.
2. State of the Art
In mass production of cabinets and other similar items, expedited methods of inserting dowels in respective cavities in the workpieces have been used. Power operated, dowel shooting guns have been proposed. These guns have been generally unreliable, with high incidence of jamming and misfiring. The problems result in excessively high maintenance costs.
A major problem is feeding dowels from a bulk source to the dowel shooting gun. Some of the systems of the prior art utilize a pneumatic feed tube such as disclosed in U.S. Pat. No. 3,906,615 for feeding one dowel at a time to the dowel shooting gun. Such a system requires complex apparatus for introducing the dowels one at a time into the pneumatic feed tube, as well as for receiving the dowels at the gun. Other systems attempt to push dowels through a flexible tube, but such systems also require complex means for feeding dowels to the feed end of the tube and for accepting dowels at the dowel gun from the tube. Jamming of dowels is a constant problem which results in numerous misfiring of the gun. The constant jamming problems and the complex apparatus results in excessive, costly maintenance on the system.
In addition, the guns of the prior art have been aligned with the cavities by the operator positioning the gun using his eyesight as his only guide. As a result, the gun is often misaligned with the cavities which results in poor, incomplete entry of the dowels into their respective cavities. As a result, the workman has to go back and hammer in all dowels to be sure that they are fully inserted into their respective cavities.
3. Objectives
A principal objective of the invention is to provide a novel dowel gun and feed apparatus that incorporates a flexible tube between a bulk supply of the dowels and the dowel gun, with relatively simple, reliable means for feeding dowels to the flexible tube to maintain the tube filled with dowels in end-to-end relationship, and simple, reliable means at the gun for accepting dowels one at a time as the dowels are pushed through the flexible tube.
Another objective of the present invention is to provide a dowel gun having an improved nose cone which has novel means for alignment of the nose cone with the cavity in the workpiece such that the dowel will be driven accurately and thoroughly into the cavity.
A further objective of the present invention is to provide a glue system incorporated with the dowel gun, wherein the glue system injects a proper amount of liquid glue into the cavity in the workpiece momentarily before the dowel is driven into the cavity.
A still further objective of the present invention is to provide a novel dowel gun and feed apparatus incorporating a flexible tube between a bulk supply of the dowels and the dowel gun, a glue system for injecting liquid glue into the cavity in the workpiece and a synchronizing timer and actuator that controls the operation of all components upon pressing of the trigger on the dowel gun to (a) inject a proper amount of glue into the cavity, (b) drive a dowel into the cavity following the injection of the glue into the cavity, (c) feed a dowel to the feed end of the flexible tube, and (d) accept a dowel into the chamber of the dowel gun for the next cycle of operation.